Try not to get too hung up on the term "binge drinking." Its used merely to denote a level of alcohol use somewhere between a little and a lot, and does not take into account the context in which the drinking occured, or anything like that.
Alcohol use researchers are usually interested in three levels of drinking:
Current Use - At least one drink in the past 30 days,
Binge Use - Five or more drinks on the same occasion (i.e., at the same time or within a couple of hours of each other) on at least 1 day in the past 30 days,
Heavy Use - Five or more drinks on the same occasion on each of 5 or more days in the past 30 days.
Slightly more than half of all Americans 12 years and older are current users, about 23 percent are binge users, and about 7 percent are heavy users.
Alcohol use is a good thing, as we all know. Alcohol abuse is a bad thing and has many negative personal and social consequences. Binge Use and Heavy Use can be (though are not necessarily) indicators of alcohol abuse, regardless of the context in which drinking occurs. This is why researchers are interested in the rates of binge drinking (and heavy drinking) in the U.S.